Several medical procedures require placement of catheters inside a blood vessel of a human body. Placement of central catheters is currently performed blindly and then confirmed with X-ray after completion of the medical procedure. X-ray imaging has adequate resolution to see tiny vessels but also would cause radiation-related complications.
Toward improved and safer care for patients including fragile infants, real-time 3-D ultrasound imaging have been proposed to supplement or gradually replace current X-ray imagers to help clinicians in performing catheter insertion operation.
The real-time and radiation-free imaging capabilities of ultrasound make it a more appealing option than X-ray-based imagers for guiding interventional procedures. Further, usage of ultrasound images in real-time, may facilitate carrying out the medical procedure in many ways, including improved outcomes for the infants and quicker completion of the medical procedures. However, ultrasound image suffers from heavy speckle noise and lower spatial resolution. It is challenging for a clinician to visualize and follow the moving blood vessels in the raw, real-time images when both hands are occupied wherein one hand holds and sweeps the probe; and the other handles the catheter delicately. According to clinical literature, improper positioning of central catheters is a suspected cause of severe complications that may lead to death of fragile patients.
On the other hand, when performing diagnostic procedures, medical personnel that perform these procedures are not trained in the use of ultrasound and thus are not used to the images procured by medical ultrasound systems. Several methods have been proposed in the prior art describing ways in which ultrasound-imaging methods can be used to enhance visualization.
Some of the limitations associated with the prior art methods include, low image quality and signal to noise ratio, large motion of vessel of interest, small size of the vessel of interest, disappearance of portions of the vessel due to artifacts etc, clutter in the data due to presence of other structures and/or vessels in the vicinity of the vessel of interest, high temporal frame rate of data and the need for segmentation and tracking to match the data acquisition speed.
In particular, one of the prior art method describes an algorithm for segmenting a vessel cross section in a single 2D slice, and then tracking the segmented vessel in a single 3D volume. This method does not address the temporal tracking aspect, i.e., the method does not describe updating the vessel segmentation over time to account for motion.
Several approaches for vessel segmentation or tubular structure segmentation have been proposed for other imaging modalities. However, the methods are not applicable to ultrasound data and temporal tracking applications.
Hence there exists a need for a method for tracking blood vessels that is simple, provides time efficient tracking of blood vessels that is easy to visualize and comprehend, robust in complex environments and computationally efficient